Fig. 5. (a) A Linear relationship (calibration graph) between the potential and the logarithm troponin concentration (log[cTn]), (b) the effect of pH on the potential response of the biosensor (Mn–MOF/PVC electrode), (c) the response time of the biosensor (Mn–MOF/PVC electrode), (d) the potential response histogram of the Mn–MOF/PVC electrode toward the (cTn) against different types of cancer biomarkers and interfering analytes. cTn cardiac troponin I, PSA prostate-specific antigen, CEA carcinoembryonic antigen, CK-total total creatine kinase, CK-MB creatine kinase-muscle/brain.